@InProceedings{MarengoVeLiPaBaAm:2004:VaSoAm,
               author = "Marengo, Jose Antonio and Vera, Carolina and Liebmann, Brant and 
                         Paegle, Julia Nogues and Baez, Julian and Ambrizzi, Tercio",
          affiliation = "Instituto Nacional de Pesquisas Espaciais, Centro de Previs{\~a}o 
                         do Tempo e Estudos Clim{\'a}ticos (INPE.CPTEC)",
                title = "Variability of the South American Low Level Jet (SALLJ) in Various 
                         Time and Spatial Scales",
                 year = "2004",
         organization = "International Clivar Science Conference, 1.",
             abstract = "Variability of the structure and spatial extension of the SALLJ is 
                         studies using a combination of various data sets (global 
                         reanalyses, PACS-SONET observations, OLR) and the data generated 
                         during the SALLJEX field experiment during the austral summer of 
                         2003. On the circulation characteristics, SALLJ composites during 
                         the warm season show the enhanced low-level meridional moisture 
                         transport coming from equatorialSouth America as well as an upper 
                         level wave train emanating from the West Pacific propagating 
                         towards South America. The intensification of the warm season 
                         SALLJ obeys to the establishment of an upper-level ridge over 
                         southern Brazil and a trough over most of Argentina. The 
                         circulation anomalies at upper and lower levels suggest that the 
                         intensification of the SALLJ would lead to an intensification of 
                         the South Atlantic Convergence Zone SACZ later on, and to a 
                         penetration of cold fronts with an area of enhanced convection 
                         ahead at the exit region of the SALLJ. Regarding the time 
                         variability, SALLJ seems to occur all year long, with the SALLJs 
                         bringing tropical moist air masses from the Amazon into southern 
                         Brazil-Northern Argentina more frequent in the warm season, and 
                         the SALLJs bringing tropical maritime air less humid than the 
                         tropical air masses coming from the Subtropical Atlantic High more 
                         frequent during the cold season. SALLJs are detected mostly during 
                         the warm season to the North of 20S, while to the south the SALLJs 
                         seem to occur all year long. The diurnal cycle shows that SALLJs 
                         are more frequent and intense between 06 and 12 Z for the warm 
                         season north of 20 S, while at the region downstream the maximum 
                         is detected between 00 and 06 Z. during the cold season. At 
                         interannual time scales, even though there is a weak tendency for 
                         stronger and more frequent warm season SALLJ episodes in years 
                         with anomalously warm surface waters in the tropical Pacific, we 
                         cannot affirm with large degree of certainty that there is a 
                         strong relationship between the occurrence of El Niņo events and 
                         the number and/or intensity of SALLJ episodes. However, the El 
                         Nino 1998 featured more frequent and intense warm season jet 
                         episodes than during La Nina 1999, and this has been demonstrated 
                         by the reanalyses, the available PACS-SONET upper-air observations 
                         and by other studies using independent data sets and regional 
                         modeling. RESUMO: O ciclo diurno do SALLJ mostra que o jato {\'e} 
                         mais forte e frequente entre as 0600 e 1200 Z durante o ver{\~a}o 
                         em latitudes ao norte de 20 °S, enquanto que na regi{\~a}o de 
                         sa{\'{\i}}da do jato o m{\'a}ximo {\'e} observado entre as 
                         0000 e 0600 Z durante a esta{\c{c}}{\~a}o de inverno. A 
                         variabilidade intrasazonal mostra associa{\c{c}}{\~o}es entre a 
                         presen{\c{c}}a da SACZ, o SALLJ e a modula{\c{c}}{\~a}o de 
                         eventos extremos de chuva na regi{\~a}o sudeste do Brasil. 
                         Aparentemente, o SALLJ ocorre durante todo o ano, mais os jatos 
                         trazendo umidade da Amaz{\^o}nia para o sul do Brasil s{\~a}o 
                         mais intensos no ver{\~a}o, e os jatos trazendo ar 
                         mar{\'{\i}}timo menos {\'u}mido (n{\~a}o tropical) do 
                         anticiclone do Atl{\^a}ntico Sul sub-tropical s{\~a}o mais 
                         frequentes no inverno. Na escala de tempo inter-anual, ainda que 
                         exista uma tend{\^e}ncia de existir mais epis{\'o}dios de jatos 
                         em anos com temperaturas do Pac{\'{\i}}fico equatorial tropical, 
                         n{\~a}o existe uma evid{\^e}ncia forte que indique com um alto 
                         grau de certeza que existe uma forte associa{\c{c}}{\~a}o entre 
                         o n{\'u}mero e intensidade de eventos jatos e a ocorr{\^e}ncia 
                         do El Nino. Em escalas de tempo mais longas, existe uma 
                         tend{\^e}ncia de ter mais epis{\'o}dios de jatos desde meados da 
                         d{\'e}cada de 1970 s, consistente com tend{\^e}ncias negativas 
                         de chuva no sul da Amaz{\^o}nia e no sul do Brasil-Norte da 
                         Argentina.",
  conference-location = "Baltimore",
      conference-year = "21-25 jun.",
           copyholder = "SID/SCD",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
           targetfile = "11863.pdf",
        urlaccessdate = "10 maio 2024"
}